<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>圆角</title>
    <style>
        .div1 {
            width: 300px;
            height: 100px;
            background-color: pink;
            border-radius: 10px;
            margin-bottom: 20px;
        }

        .div2 {
            width: 300px;
            height: 100px;
            background-color: green;
            border-radius: 50px;
            margin-bottom: 20px;
        }

        .div3 {
            width: 300px;
            height: 300px;
            background-color: red;
            border-radius: 50%;

        }
    </style>
</head>

<body>
    <div class="div1"></div>
    <div class="div2"></div>
    <div class="div3"></div>

</body>

</html>